Method and means for mounting and controlling peltier elements



y 7, 1954 A. KUCKENS ETAL METHOD AND MEANS FOR MOUNTING AND CONTROLLINGPELTIER ELEMENTS 2 Sheets-Sheet 1 Filed March 16, 1962 y 7, 1964 A.KUCKENS ETAL 3,139,734

METHOD AND MEANS FOR MOUNTING AND CONTROLLING PELTIER ELEMENTS FiledMarch 16, 1962 2 Sheets-Sheet 2 O I I I I t I =CURRENT IN AMPERE THROUGHPELTIERE ELEMENTS I, TEMPERATURE OF WATER SIDE IN CENTIGRADE P= STARTINGPOINT OF THERMOSTAT CHANGE l I I l I I I I I I I l l 1. I I

I I I II t l CURRENT IN AMPERE THROUGH PELTIERE ELEMENTS I TEMPERATUREOF WATER SIDE IN CENTIGRADE P= STARTING POINT OF CONTROL United StatesPatent 3,139,734 METHUD AND MEANS FOR MOUNTING AND CONTROLLING PELTIERELEMENTS Alexander Kiiclrens, Willistrasse 43, Hamburg 39, Germany, andWolfgang Niehaus, Sandheide-lS, Hamburg- Neugrahen, Germany Filed Mar.16, 1962, Ser. No. 130,288 Claims priority, application Germany Mar. 16,1961 2 Claims. (Cl. 62-3) This invention relates to a method and meansfor mounting and control of Peltier elements.

In practical use of Peltier elements it is at present feasible toachieve a temperature difference of between 50 and 60 C. With constantcurrent supply the Peltier element has a tendency to continuouslydisplace this temperature range upwardly. In other words, if in aninstallation intended to have a temperature of 0 C. 0n the cold side anda temperature of maximum 60 C. on the warm side, the last mentionedtemperature should increase to, e.g., 100 C., the temperature on thecold side might rise to 40 C.

In order to avoid such an increase above a maximum temperature on thewarm side of a Peltier element it is necessary to provide fortransmission or" heat to some medium from the element. Certaindifiiculties are en countered in this connection. One possibility wouldbe to greatly enlarge the heat transmission surface of the warm side byadding a pack of laminae. This involves, however, considerable costswhich as a rule are not economically practicable.

Another possible solution would be to bring the warm side of the elementin contact with a cooling medium, such as water. Such a medium wouldhave to be circulated in order to transport sufiicient amounts of heat,and this would involve the use of a pump aggregate, a source of runningwater with attendant loss of heat, or a closed water circuit with meansfor continuously cooling the water. In either case, and regardiess ofWhether air or Water cooling is employed, a portion of the produced heatenergy would be unnecessarily wasted, whereby the economical elficieucyof the Peltier element would be jeopardized, particularly in the case ofhigh wattage output.

The ideal solution would appear to be a combination with a hot watersystem capable of operating the cooling means and at the same time ofdelivering hot Water. However, a water filled container which issuiticiently large to absorb the continuously supplied heat caloriescannot be used when it also must deliver hot water of, for instance,upto 100 C.

The present invention provides the solution of all these problems.

An object of the invention is to provide a method and means whereby thewarm side of the Peltier element is not connected directly to a hotwater vessel but rather with an uninsulated buffer vessel which is sodimensioned that it for long periods can absorb the freed heat calories.Directly to this buffer vessel an insulated hot water battery may beconnected which receives the preheated water from the buffer vessel.Thereby the heat calories freed from the Peltier element can be usefullyutilized.

The problem which may arise in connection with such an installation isthat due to insufficient hot water consumption from the hot waterbattery the heat calories in the butter vessel may accumulate to such anextent that the temperature on the cold side of the Peltier elementrises unduly.

Therefore, it is another object of the invention to provide means, e.g.,thermostat controlled means, whereby 3,139,734 Patented July 7, 1964 thebufier vessel upon reaching a predetermined temperature is emptied andfilled with fresh water.

A further object of the invention is to provide means whereby uponreaching a predetermined temperature in the buffer vessel a currentrestriction for the Peltier element occurs in such a way that the amountof supplied heat calories no longer is sufficient to bring the buttervessel to the maximum temperature since said vessel is not insulated andalso, e.g., through direct or indirect enlargement of its transmissionsurfaces, including the evaporation surface of the water, dissipatesmore heat calories than supplied from the warm side of the thusthrottled Peltier element.

The invention is described below with reference to the accompanyingdrawings, in which:

FIG. 1 is a diagrammatic elevational view, partly in section, of oneembodiment of the invention,

FIG. 2 is a similar view of another embodiment, and

FIGS. 3 and 4 are diagrams illustrating two different forms of theinventive method.

In FIG. 1 an insulated container 1 forms a cooling chamber 2 into whichthe cold side 3 of a Peltier element, or battery, 15 extends through oneof the walls of the container 1. The warm side 4 of the Peltier element15 is located in a vessel 5 which is filled with water up to the level6. A water supply pipe 7 extends into the vessel 5 from above andcontains a valve 8, e.g., an electrically operated valve, which controlsthe connection of the pipe 7 with a water supply system. An outlet pipe9 extends into the vessel 5 to form an over flow means, and the vessel 5is provided with a thermostat 10 which through a connection indicated at20 controls the opening and closing of the valve 8 in a known manner.Means (not shown) are provided for conmeeting the Peltier element 15 toasuitable power net. When through the action of the Peltier element 15the temperature of the water in the vessel 5 exceeds a predeterminedvalue, the thermostat 10 causes the valve 8 to open so that fresh wateris supplied to the vessel 5 through the pipe 7. As indicated, this freshwater will enter the vessel 5 adjacent the bottom thereof and thus causethe warm water thereabove to be discharged through the overflow pipe 9.When the water temperature has been sufiiciently lowered, the thermostatcauses the valve 3 to close. The vessel 5 may, of course, be providedwith a suitable outlet valve (not shown) for use in emptying the samewhen required.

In FIG. 1 a hot water battery 11 is shown in dashed lines. This hotwater battery may be any kind of heat exchanger, a hot water boiler, orother similar device. If suitable connections (not shown) with thevessel 5 are provided, and if the hot water consumption in said battery11 is continuous and of suificient magnitude, the the fresh water supplyprocedure described above is, of course, superfluous. It would berequired only if and when the output from said battery 11 becomesinsufficient or too irregular for the amount of heat calories in thevessel 5.

In the embodiment of the invention shown in FIG. 2 the arrangement ofthe container 1 with its cooling cham her 2, the buffer Vessel 5, andthe Peltier element 15 with its cold side 3 and warm side 4 issubstantially similar to that of FIG. 1. The location of the supply pipe7 with its valve 8 is changed as shown, and the thermostat 10' is alsodifferently disposed.

An insulated hot water tank 11' is connected with the vessel 5 by meansof a pipe 12, and through this arrangement it is obvious that the waterlevel 6 in the tank 11' will be substantially equal to the water level 6in the vessel 5. It will be noted that the vessel 5 in this case has nooverflow pipe corresponding to the pipe 9 in FIG. 1. On the other hand,there is an operative connection, indicated at 22, of well known kindbetween the thermostat 10 and the electrical power supply to the Peltierelement 15 for a purpose which will be explained below. There may, ofcourse, also be separate heating means for bringing the preheated watersupplied to the tank 11' from the vessel 5 to a desired hightemperature.

In operation, hot water is occasionally withdrawn from the tank 11 asrequired for one purpose or another, and only a sufficient amount offresh water to replace said withdrawn amount is automatically suppliedthrough the pipe 7 and valve 8 as, e.g., under the control of a waterlevel contact means 24 in vessel 5 with a connection 26 to the valve 8.It is obvious, therefore, that in the case of insufficient withdrawalfrom the tank 11' the water temperature in the vessel 5 will tend toincrease.

If the thermostat 10 were connected to the power supply for the Peltierelement in such a way as to shut olf said power supply when apredetermined temperature, e.g., 60 C., is exceeded in the vessel 5,then the cooling eifect in the chamber 2 and the heating effect invessel 5 would both be interrupted. The Peltier element 15 is heatconducting and thus the result would be that the temperature in thechamber 2, e.g., C., would gradually increase while the temperature inthe vessel would decrease. The desired cooling effect in the container 1would be lost.

In one form of the present invention the connection between thethermostat and the power supply is so arranged that at a certaintemperature of the water in the vessel 5 below the predetermined maximumtempera: ture the thermostat 10' causes the normal power supply to beinterrupted and replaced by a reduced power supply. The efiect of such achange is diagrammatically illustrated in FIG. 3 in which the current.(I) in amperes is indicated on the vertical axis while the temperature(I) in degrees centigrade C.) is markedon the horizontal axis.

In the example illustrated in said FIG. 3 the thermostat 10' switches tothe reduced power supply at a water temperature in the vessel 5 of 500., thus causing the current to drop from 20 amperes to 2 amperes. Thereduced current should be chosen so as to produce a heating effect whichrenders the heat supply over the Peltier element to the vessel 5 equalto or less than the heat loss from said vessel 5. Heat transfer to thecooling chamber 2 will thus be prevented.

FIG. 4 illustrates how the same result can be achieved without the aidof a thermostat controlled power source. In this case, a temperaturesensitive resistance is disposed in the vessel 5 and connected in thecircuit. In the example illustrated, the resistance is adapted to beginits action at 50 C. and then gradually reduce the heat supply to zero at60 C. This zero point will, however, not be reached since the gradualthrottling of the heat supply over the Peltier element prevents it, asthere is a continuous loss of heat from the vessel 5 through its walland from the water surface. Accordingly, the cooling 7 effect in thechamber 2 is preserved in this case also.

Modifications within the scope and spirit of the invention will occur tothose skilled in the art.

What we claim is:

1. In cooling means utilizing the Peltier effect, means 7 defining acooling chamber, means defining a substanautomatically cause reductionof the power supply to the Peltier element when the temperature in thewater container rises toward a predetermined value whereby totalinterruption of the cooling effect of the Peltier element in the coolingchamber is prevented regardless of the rate of water tapping from thehot water tank.

2. Cooling means as set forth in claim 1, in which said heat sensitivemeans comprises a thermostat.

References Cited in the file of this patent UNITED STATES PATENTS2,497,450 Gygax Feb. 14, 1950 2,795,938 Galazzi June 18, 1957 2,998,707Meess et al Sept. 5, l961 3,008,299 Sheckler Nov. 14, 1961

1. IN COOLING MEANS UTILIZING THE PELTIER EFFECT, MEANS DEFINING A COOLING CHAMBER, MEANS DEFINING A SUBSTANTIALLY UNINSULATED WATER CONTAINER, A POWER SUPPLIED PELTIER ELEMENT CONNECTED WITH ITS COLD SIDE TO SAID COOLING CHAMBER AND HAVING ITS WARM SIDE IN DIRECT METALLIC HEAT CONDUCTIVE CONNECTION WITH SAID WATER CONTAINER, MEANS DEFINING A HOT WATER TANK, MEANS CONNECTING SAID HOT WATER TANK WITH SAID WATER CONTAINER SO AS TO MAINTAIN SUBSTANTIALLY THE SAME WATER LEVEL IN SAID CONTAINER AND TANK WHEREBY WATER IS WITHDRAWN FROM SAID WATER CONTAINER WHEN WATER IS TAPPED FROM SAID HOT WATER TANK, AND HEAT SENSITIVE MEANS ASSOCIATED WITH SAID WATER CONTAINER TO AUTOMATICALLY CAUSE REDUCTION OF THE POWER SUPPLY TO THE PELTIER ELEMENT WHEN THE TEMPERATURE IN THE WATER CONTAINER RISES TOWARD A PREDETERMINED VALUE WHEREBY TOTAL INTERRUPTION OF THE COOLING EFFECT OF THE PELTIER ELEMENT IN THE COOLING CHAMBER IS PREVENTED REGARDLESS OF THE RATE OF WATER TAPPING FROM THE HOT WATER TANK. 